Miss Galvin’s brother, Andrew, 31, is appealing for people to help police find the person responsible.

Mr Galvin, who is his sister’s carer, said: “I would just say to this person, ‘if you have a conscience, then come forward’.

“The vehicle must have sustained significant damage to the windscreen and bonnet.

“My message to the community, to taxi drivers, mechanics, postmen, neighbours is, if you suspect you know who did this then contact the police.” Miss Galvin, was walking the family’s Jack Russell, Pat, at about 1.30pm on Wednesday when she was hit.

She was airlifted to the specialist trauma centre at Queen’s Hospital, in Romford, and later transferred to the Royal London Hospital, in Whitechapel.

Mr Galvin said his sister was awake, but could not remember much about the crash.

He said: “The last thing she remembers is walking Pat in the park.

“I was at work when the news came through. Pat is microchipped and the emergency services rang to say the dog’s walker had been in an accident. I arrived home, saw the air ambulance and my heart just sank.”

Miss Galvin had an operation at the weekend to insert metal pins in to her legs.

The family, of Clay Hill Road, Basildon, are waiting to find out when doctors can next operate.

Mr Galvin said: “She will be in hospital for about six months, but it could be a year before she walks again. Martina was in good spirits for the first few days, but now she is getting frustrated.

Promoted stories

Because she is autistic she cannot understand why she is not allowed out. She is feeling pretty low.

“My sister was totally innocent.

The person who did this was very cold. I would just ask anyone with information to please come forward.”

Mr Galvin thanked the emergency services who helped his sister and people who have posted messages of support on her Facebook page.

Share article

Anyone with information should contact PC Jenny Pirie, at the serious collision investigation unit at Essex Police, on 101.

Ipsoregulated

This website and associated newspapers adhere to the Independent Press Standardards Organisations's Editors' Code of Practice. If you have a compaint about editorial content which relates to inaccuracy or intrusion, then please contact the editor here. If you are dissatisfied with the response provided you can contact IPSO here